basically if you plug the oil ports on the sti cams that final lobe wont try and force oil into the AVCS that aren't there.
some people on here believe that you still need the actuators for teh avcs cause they are part of teh sti cam. If you run the sti cam blocked/plugged, on wrx heads it's a drop and play. Just set valve clearance in spec with the right buckets and slap the valve covers on and rip. I'm not sure if the sti cams have a steep enough lobe to require a bumped idle to stop from "caming" but you shoud know after some time.
I did a lot of looking into this, but decided the sti cams were not really a big increase over the stock wrx ones, and frankly I didn't care enough I wanted my car back together.